This invention relates to refrigeration systems and, more particularly, to fuel systems for refrigeration systems.
Refrigeration systems often incorporate a diesel engine to drive the compressor and blower components. Diesel engines operate by compressing a quantity of air in a cylinder and then injecting fuel into the compressed air. The heat of the compressed air spontaneously ignites the fuel, causing the cylinder volume to expand and drive a shaft.
A number of fuel injection systems are known to exist for introducing fuel into the cylinder in a diesel engine. In a distributor type injection system, a single injector pump and plunger mechanism move the fuel from the fuel filter to a distributor that distributes the fuel to the cylinders in proper sequence and time. In an inline-injection type system, each cylinder is associated with its own injection pump and plunger mechanism. A camshaft with a timing device drives the plungers and introduces fuel into the cylinders in the proper sequence and at the proper time.
Diesel engines can be difficult to start if the fuel line contains an excess of air. Air can get into the fuel line when the fuel level drops to the point where the fuel pump receives air. In this situation, the engine typically will not start until the air is removed from the fuel line. To do this, diesel fuel systems commonly include a mechanism for bleeding the air out of the fuel line.
Diesel fuel injection systems, particularly those with inline fuel injection systems, commonly do not exhibit symptoms of low fuel prior to air being drawn by the fuel pump. The engine typically will die suddenly, without exhibiting any fluctuations or erratic RPM levels. When the engine shuts down, the engine will already have drawn a large quantity of air into the fuel line, making it difficult to restart the engine. This problem is especially prevalent when the refrigeration system is used in connection with a truck trailer where the truck driver cannot constantly monitor the fuel level.